1. Pub Health & Canadian Immunization System

Infectious disease emergence involves 2 main steps

An agent is introduced into a new host population.

The agent is established and transmitted within the new host population

R0 or R-nought

Reproductive number of a disease in a naïve population.

Essentially it is a measure of how many people one sick person can infect if there are no control measures in an unimmunized population (control measures depend on how a disease is spread).

• If a disease has an R0 < 1 then it will fade over time as it takes more than 1 sick person to infect another.

• An R0 of 1 would keep the same number sick all the time.

• An R0 of > 1 means it will spread and the higher the number the faster the spread.

What is Rt/Re

Rt/Re is the effective reproduction number

Rt/Re represents the average number of new infections that would occur in a setting of non-pharmaceutical measures as well as background immunity because of natural infection or vaccine induced immunity.

Measures could include isolation, masks, education etc.

Effective measures vary by infection type

Herd immunity threshold is defined by

1 - (1/R0)

Herd immunity definition

When a sufficient proportion of a population is immune to an infectious disease (through vaccination and/or prior illness) to make its sustained spread from person to person unlikely

Has been used to establish critical vaccination level or threshold

Challenge: vaccination coverage difference between groups in a population

ASK approach

Acknowledge your client’s concerns

Steer your conversation

Knowledge - know the facts well!

Vaccine Development and Delivery: Step 1

Lab Studies:

• Antigen research

• epidemiology of a disease

• infectious agent

Vaccine Development and Delivery: Step 2

Pre-Clinical

• Animal studies

• immunogenicity: immune response needed to prevent disease

• challenge studies in animal models

• Safety studies: no toxicities that would prevent their use in people

Vaccine Development Step 3 (Clinical Phase I)

• Human Studies (10-100)

• Immunogenicity

• Local/systemic reactions

Vaccine Development Step 3 (Clinical Phase II)

• Human studies (50-500)

• optimal dose/schedule in target population

• safety assessment

Vaccine Development Step 3 (Clinical Phase III)

• HUman Studies (300-30,000)

• Efficacy in target populations

• Safety assessment

Passive Vaccine Monitoring

Canadian Adverse Events Following Immunization Surveillance System (CAEFISS)

Active Vaccine Monitoring

Immunization Monitoring Program ACTive (IMPACT)

Who Makes Recommendations for Vaccine Use?

National Advisory Committee on Immunization (NACI)

• Falls under the Public Health Agency of Canada

• Comprised of recognized experts - pediatricians, infectious diseases, immunology, pharmacy, nursing, epidemiology, pharmacoeconomics, social science and public health

• Provides the scientific perspective

• Makes recommendations for the use of vaccines independent of cost considerations. Only based on evidence and efficacy

Who Makes Recommendations for Immunization Program Planning?

Canadian Immunization Committee (CIC)

• Comprised of federal/provincial/territorial public health officials

• Review and provide recommendations on immunization program planning (e.g. cost-analysis of vaccines vs overall benefit to society)

• Established to develop national goals and targets

Alberta Advisory Committee on Immunization (AACI) Role

• reviews vaccine recommendations

• provides scientific expert recommendations to Alberta Health for new or enhanced immunization programs

Immunization Steering Committee (ISC) Role

develop policies and high-level program guidelines

Decisions are made based on a variety of criteria including a cost benefit analysis to determine if a vaccine will be publicly funded.